1. Field of the Invention
The invention relates generally to a system including methods and apparatus for deforming a plurality of planar spring elements such that each element produces a precise load upon deflection to a particular position, and in particular, to bending load/support arms which resiliently support "flying" read/write heads of magnetic disk drive systems above the spinning disk.
2. Description of the Prior Art
Efforts to improve magnetic disk drive data storage systems ultimately focus on increasing the density of data recorded or stored in the media of the disk. The interaction between the recording heads and the disk media has been described as "where the tire meets the road" in the race to increase data storage density.
However, the recording or read/write heads of such systems do not actually touch the surface of the media spinning below, but rather, fly on air bearings gimbaled to a support or suspension arm extending from carriage structures. Storage density is inversely related to the height which the head flies above the spinning surface of the depth, i.e. lower flying height means greater storage density. The typical flying heights of the air bearing above the spining media is on the order of micrometers and nanometers, i.e., 10.sup.-6 to 10.sup.-9 meters. Such small distances mean that achievable storage density in any disk drive system is critically dependent on the element supporting the flying head above the spining surface of the disk, or "the suspension holding the tire to the road."
The support arm to which the flying head is gimbled provides primary suspension for resiliently counter balancing aerodynamic forces driving the air bearing away from the surface of the spining disk. Such support arms typically include a base, a flexure section, a relatively ridged beam section and a tip. The gimble mount attached to the flying head is secured at the tip of the support arm, and a mounting or reinforcing block is secured at its base.
The flexure section is typically bent to provide an angular relationship between the beam and base sections when the arm is not constrained. When the support arm is secured to a carriage of a disk drive, the flying head gimbled at the tip of the arm initially bears inwardly against the surface of the disk media straightening the angle of the flexure section. Upon spinning the disk, the head lifts to flying height further straightening the flexure section. The inward force imparted to the flying head by the support arm is typically referred to as the "gram load," and is measured in the cgs system). The gram load imparted by the arm to the flying head at flying height is controlled by both the degree and nature of the bend in the flexure section of the arm.
It is desirable to have a reliable and repeatable process for precisely bending the flexure sections of a large quantity of such support arms such that each arm will impart a known gram-load to a flying head at flying height when incorporated into a disk drive.